Base for electric discharge devices



March 1, 1932. MULLANEY 1,847,886

BASE FOR ELECTRIC DISCHARGE DEVICES Filed June 18, 1926 InVentor': Dudley 7\. Mul laney.

l iis Attorney.

Patented Mar. 1, 1932 PATENT OFFICE DUDLEY A. MULLANEY, OF SCHENECTAIJY,

NEW YORK, ASSIGNOR TO GENERAL ELEC- TRIO COMPANY, A CORPORATION OF NEW YORK BASE FOR ELECTRIC Application filed June 18,

tubes.

Previously, in three-element electric discharge devices having terminals at opposite ends thereof it has been customary to employ a base member having a flat portion of insulating material and a circular metal portion attached to the fiat portion and to the tube, the terminals for the cathode and controle element or grid being mounted on the insulating portion of the base. Usually the control terminal has been mounted between the cathode terminals and embedded in the insulating material, and as thus arranged the lead from the grid has been brought from one side of the tube and through the center of the insulating base and then soldered to the grid terminal.

The base as thus described has certain disadvantages. The circular metal portion tends to become heated due to induced eddy current, when employed in connection with very high frequency currents such as are encountered in the use of relatively short wave lengths; the connection between the insulation and metal portion of the base, and

" between the insulation and terminals tends to become defective; and the electric leakage path between the control and filament terminals is comparatively short.

According to the present invention, an integral vitreous heat resistant base is mounted on one end of an electric discharge device and provided with a series of terminals each of which is rigidly but detachably mounted on the base and provided with an opening within which the leads from the electrodes may be soldered. The terminal for the control electrode is moreover so mounted 011 the base that it is spaced from the base for the greater portion of its length thus providing a relatively long leakage path between it and the cathode terminals.

The novel featureswhich I believe to be characteristic of my invention are set forth with particularity in the appended claims.

My invention itself, however, will best be DISCHARGE DEVICES 1926. Serial No. 116,945.

understood from reference to the following specification taken in connection with the accompanying drawings in which Fig. l is an elevation of an electric discharge device embodying the features of my invention; Fig. 2 is a cross sectional view of my iniproved form of base showing the manner of attaching the base to an electric discharge device; while Fig. 3 is a plan view of the base member showing the arrangement of the electric terminals thereon.

Referring to the drawings, I have indicated at 1 an electric discharge device having the usual anode, cathode and grid or control element, the anode being connected to an exterior metal terminal or base 2. Mounted on the opposite end of the discharge device is an insulating base 3 made of transparent, heat resistant, vitreous material. The material used in the present instance is a boro-silicate glass containing an appreciable amount of aluminum and is generally known in the arts and trade as Pyrex or Pyrex glass.

The lower portion of base 8 is provided with an annular recess 4 adapted to hold a cement 5 by means of which the base may be permanently and rigidly secured to the device 1. The flat portion of base 3 is provided with a plurality of openings 6 extending therethrongh, the outer ends of the openings being surrounded by annular elevated portions as indicated at 7, while the inner ends of the openings are provided with counter-sunk portions 8 which are somewhat greater in extent than a semicircle and each provided with a flattened portion 9. A pair of hollow, screw threaded cathodeterminals 10 and 11 having flanges at one end thereof, as indicated at 12, are inserted through two of the openings in the base 3 and detachably secured thereto by means of nuts 13 and 14. The flanged portions 12 of the terminals fit within the counter-sunk portions 8 of openings 6, the flattened part of the counter-sunk portion preventing rotation of the terminals when nuts 13 and 1% are tightened on the screw threaded portions of the terminal.

A flat substantially rectangular grid terminal 15 is mounted between the cathode terminals 10 and 11. Terminal is provided with a pair of extensions 16 having openings adapted to register with the pair of openings 6 in the base 3. Screw threaded elements 1? and 18 extend through the openings in the base and the extension 16 and are engaged the opposite ends thereof y nuts 19'to thereby secure the terminal. 15 to the base 3. Screw threaded member 17 is provided with an opening theret-L 'ough adapted to receive a lead 20 connected to the control element of the tube.

As thus arranged the terminals are rigidly but detachably mounted on the base member, the leads from the electrodes to the terminals on the base are spaced convenient distances apart and the leakage distance etw-een the control terminal and the cathode terminals, due to the spacing of the control terminal from the base, is substantially greater than one half the distance between the cathode terminals.

\Vhat I claim as new and desire to secure by Letters Patent of the United States, is

1. In combination, an insulating base adapted to be mounted on an electric dis charge device, a pair of electric terminals mounted on the base, .athird terminal mounted on the base between said pair of terminals, the third terminal being provided with a pair of spaced openings whereby it may be secured to the base, the third terminal being spaced from the base except at the points of attachment thereto.

2. In combination, an insulating base adapted to be mounted on an electrical discharge device, a plurality of openings in said base and an elongated terminal secured in a pair of said openings and spaced from the base except at the points of attachment.

3. In combination, an electron discharge device, an insulating base mounted thereon and having openings, an electric terminal secured to the base by attachment at a plu rality of said openings, a substantial. portion of said terminal being spaced from said base, and an electrical connection between the dis charge device and said terminal passing through one of the points of attachment.

4:. In combination, an insulating base adapted to be mounted on an electrical discharge device, a pair of openings in said base adapted to receive electrical conductors and a third opening in said base out of alignment with said pair of openings, a terminal secured in the third opening having a portion extending toward a position intermediate between the first mentioned openings and spaced from the base whereby the electrical leakage distance as measured between either of said pair of openings and said third opening, is increased.

5.'In combination, an insulating base adapted to be mounted on an electrical discharge device, a pair of terminals mounted said pair of terminals.

In witness whereof, I have hereto set my hand this 17th day of June, 1926.

DUDLEY A. MULLANEY. 

